The present invention relates generally to fastening devices.
In the well drilling industry, it has been an established practice for many years to utilize deadline cable anchoring apparatus of the general type disclosed in U.S. Pat. No. 3,056,287, and which included a hydraulic sensing device for indicating the load tension forces on the anchored cable.
In the typical cable anchoring and load sensing apparatus, the cable is connected to a snubbing drum that is operable under the applied cable tension forces to relatively separate upper and lower sets of coupling ears which are respectively coupled by means of pivot pins to connection lugs of a hydraulic load sensing device having a load responsive diaphragm.
Large numbers of these existing cable anchoring and load sensing apparatuses have been fabricated with steel pivot pins for coupling the sensing device lugs to the set of ears of the cable anchoring apparatus. It has now been discovered that, when these couplings with the steel pivot pins are exposed to the rigors of the elements under field operating conditions, the pins become corroded and cause the couplings that connect the sensing device to the ears of the cable anchoring apparatus to seize and become fixed. As a result, flexing forces are transmitted to the diaphragm of the sensing device and ultimately cause its deformation and failure.
The replacement of the damaged diaphragms by the field servicemen has thus presented a long-standing and continuing anchor problem. Servicemen usually resort to the drastic procedure of utilizing a sledge hammer to drive out the stuck pivot pins, which at times may take several hours of labor. Where this procedure failed, the serviceman would melt out the stuck pivot pin with an acetylene torch, a procedure which usually damaged the coupling ears of the cable anchoring apparatus and required expensive replacements.
The present invention not only solves the problem of removing the stuck corroded pivot pins in the field in a facile and economical manner, but also provides an apparatus and method whereby the coupling pivot pins and associated bearing surfaces may be up-dated by the installation of new pivot pins and associated bearing surfaces of a substantially non-corrosive material, such as stainless steel.
For such purpose, there is provided a unique hydraulically actuated apparatus in which a yoke frame structure is so designed that it can be operatively attached to the ears of the coupling containing the stuck pivot pin. The cylinder of a hydraulic cylinder-piston actuator assembly is connectable at one end with the frame structure in a manner such that the piston will be in axial alignment with the stuck pin, and a connected pusher element, engaged with the adjacent end of the stuck pivot pin, will be operative upon energization of the hydraulic actuator to apply a pushing force against the stuck pivot pin and axially force it out of the bearing bore surfaces formed in the coupling ears. Provision is made for reconnecting the other end of the cylinder of the hydraulic actuator to the frame structure so that the piston will move in a pulling direction, whereby upon attachment of a broaching tool to the piston, the bearing bores of the coupling may be broached to a predetermined enlarged diameter of a size to receive new bearing liners of a substantially non-corrosive material such as stainless steel, and an appropriate inner diameter to provide bore bearing surfaces for a replacement new pivot pin of a substantially non-corrosive material such as stainless steel.